<!DOCTYPE html>
<html>

<head>
    <meta http-equiv="content-type" content="text/html; charset=utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no">
<meta name="apple-mobile-web-app-capable" content="yes"/>
<title>2.4 GPS伪随机码 | pansis.io</title>
<link rel="shortcut icon" href="https://github.pansis.site/favicon.ico">
<link href="https://github.pansis.site/styles/main.css" rel="stylesheet">
<link href="//at.alicdn.com/t/c/font_1678829_b85ccgkdqkr.css" rel="stylesheet">
<link href="//cdnjs.cloudflare.com/ajax/libs/KaTeX/0.10.0/katex.min.css" rel="stylesheet">
<link rel="alternate" type="application/rss+xml" title="pansis.io » Feed" href="https://github.pansis.site/atom.xml">
        <meta name="description" content="一、截短码
1、定义
在线性移位寄存器中加入状态监测器，用来截断原本的伪随机码，使其周期变短。
2、特点
截短序列产生器不再是线性移位寄存器，故不能再用特征多项式来描述。，只能用反馈逻辑函数来描述。
3、实例图


二、复合码
1、定义
由..." />
        <meta name="keywords" content="组合导航原理" />
        <!-- OG -->
        <meta property="og:locale" content="zh_CN">
        <meta property="og:title" content="2.4 GPS伪随机码" />
        <meta property="og:type" content="article" />
        <meta property="og:description" content="一、截短码
1、定义
在线性移位寄存器中加入状态监测器，用来截断原本的伪随机码，使其周期变短。
2、特点
截短序列产生器不再是线性移位寄存器，故不能再用特征多项式来描述。，只能用反馈逻辑函数来描述。
3、实例图


二、复合码
1、定义
由...">
        <meta property="og:url" content="https://github.pansis.site/post/2.4 GPS伪随机码/" />
        <meta property="og:site_name" content="pansis.io">
        <meta property="og:updated_time" content="2023-10-10">
        <meta property="og:image" content="" />
        <meta property="og:image:secure_url" content="">
        <meta property="og:image:alt" content="2.4 GPS伪随机码">
        <!-- Twitter (post.ejs) -->
        <meta name="twitter:card" content="summary_large_image">
        <meta name="twitter:title" content="2.4 GPS伪随机码">
        <meta name="twitter:description" content="一、截短码
1、定义
在线性移位寄存器中加入状态监测器，用来截断原本的伪随机码，使其周期变短。
2、特点
截短序列产生器不再是线性移位寄存器，故不能再用特征多项式来描述。，只能用反馈逻辑函数来描述。
3、实例图


二、复合码
1、定义
由...">
        <!-- <meta name="twitter:site" content="@WBoy0609">
        <meta name="twitter:creator" content="@WBoy0609"> -->
        <meta name="twitter:image" content="">
</head>

<body>
    <div class="main animated">
        <div class="header animated fadeInDown">
    <div class="site_title_container">
        <div class="site_title">
            <a href="https://github.pansis.site">pansis.io</a>
        </div>
    </div>
    <div class="my_socials">
        
            
        
            
        
            
        
            
        
            
        
            
        
            
        
        <a href="https://github.pansis.site/atom.xml" title="rss" target="_blank"><i class="iconfont icon-rss"></i></a>
    </div>
</div>

    <div class="header_menu">
        
            
                <a href="/" class="menu">首页</a>
            
        
            
                <a href="/tag/GWAaV2nvk/" class="menu">程序设计课程</a>
            
        
            
                <a href="/tag/24hangc" class="menu">比赛</a>
            
        
            
                <a href="/tag/L7r9STb75/" class="menu">Python教程</a>
            
        
            
                <a href="/tags" class="menu">分类</a>
            
        
        <div class="gridea-search-div">
            <form id="gridea-search-form" action="https://github.pansis.site/search/">
                <input class="gridea-search-input" autocomplete="off" spellcheck="false" name="q"/>
            </form>
        </div>
    </div>

            <div class="autopagerize_page_element">
                <div class="content">
                    <div class="post_page">
                        <div class="post animated fadeInDown">
                            <div class="post_title post_detail_title">
                                <h2>
                                    2.4 GPS伪随机码
                                </h2>
                                <span class="article-info">
                                    2023-10-10, 425 words, 2 min read
                                </span>
                            </div>
                            <div class="post_content markdown">
                                <p class="md_block">
                                    <span class="md_line md_line_start md_line_end">
                                        <h2 id="一-截短码">一、截短码</h2>
<h4 id="1-定义">1、定义</h4>
<p>在线性移位寄存器中加入状态监测器，用来截断原本的伪随机码，使其周期变短。</p>
<h4 id="2-特点">2、特点</h4>
<p>截短序列产生器不再是线性移位寄存器，故不能再用特征多项式来描述。，只能用反馈逻辑函数来描述。</p>
<h4 id="3-实例图">3、实例图</h4>
<img src="http://cos.pansis.site/202310102004256.png/abc123" alt="image-20231010200436065" style="zoom:50%;" />
<img src="http://cos.pansis.site/202310102005244.png/abc123" alt="image-20231010200504056" style="zoom:50%;" />
<h2 id="二-复合码">二、复合码</h2>
<h4 id="1-定义-2">1、定义</h4>
<p>由两个或两个以上的短码异或成为复合码</p>
<h4 id="2-实例">2、实例</h4>
<img src="http://cos.pansis.site/202310102006786.png/abc123" alt="image-20231010200602425" style="zoom:33%;" />
<h4 id="3-特性">3、特性</h4>
<p>1、复合码长度</p>
<img src="http://cos.pansis.site/202310102006307.png/abc123" alt="image-20231010200620210" style="zoom:33%;" />
<p>2、复合码自相关函数</p>
<img src="http://cos.pansis.site/202310102006084.png/abc123" alt="image-20231010200639965" style="zoom:33%;" />
<p>增⼤码长，⼤⼤改善了自相关函数的特性，缩短了寻找最 ⼤自相关值的过程</p>
<h2 id="三-ca码">三、C/A码</h2>
<h4 id="1-功能">1、功能</h4>
<p>用于分址、搜捕卫星信号和粗测距，具有一定抗干扰能力</p>
<h4 id="2-产生方法">2、产生方法</h4>
<p>由两个10级移位寄存器产生</p>
<img src="http://cos.pansis.site/202310101516484.png/abc123" alt="image-20231010151645431" style="zoom:33%;" />
<img src="http://cos.pansis.site/202310101515195.png/abc123" alt="image-20231010151556953" style="zoom:33%;" />
<p>不同卫星有不同的PRN编号，其相位选择器不同，导致其<span class="katex"><span class="katex-mathml"><math><semantics><mrow><msub><mi>G</mi><mrow><mn>2</mn><mi>i</mi></mrow></msub></mrow><annotation encoding="application/x-tex">G_{2i}</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.83333em;vertical-align:-0.15em;"></span><span class="mord"><span class="mord mathdefault">G</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.31166399999999994em;"><span style="top:-2.5500000000000003em;margin-left:0em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight">2</span><span class="mord mathdefault mtight">i</span></span></span></span></span><span class="vlist-s">​</span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span></span></span></span>不同。</p>
<h4 id="3-基本特性">3、基本特性</h4>
<ul>
<li>时钟脉冲速率：<span class="katex"><span class="katex-mathml"><math><semantics><mrow><mn>1.023</mn><mi>M</mi><mi>b</mi><mi>i</mi><mi>t</mi><mi mathvariant="normal">/</mi><mi>s</mi></mrow><annotation encoding="application/x-tex">1.023Mbit/s</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord">1</span><span class="mord">.</span><span class="mord">0</span><span class="mord">2</span><span class="mord">3</span><span class="mord mathdefault" style="margin-right:0.10903em;">M</span><span class="mord mathdefault">b</span><span class="mord mathdefault">i</span><span class="mord mathdefault">t</span><span class="mord">/</span><span class="mord mathdefault">s</span></span></span></span></li>
<li>码长： <span class="katex"><span class="katex-mathml"><math><semantics><mrow><mn>1023</mn><mi>b</mi><mi>i</mi><mi>t</mi></mrow><annotation encoding="application/x-tex">1023bit</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.69444em;vertical-align:0em;"></span><span class="mord">1</span><span class="mord">0</span><span class="mord">2</span><span class="mord">3</span><span class="mord mathdefault">b</span><span class="mord mathdefault">i</span><span class="mord mathdefault">t</span></span></span></span>，很短，易于捕获(捕获码)</li>
<li>码元宽度 <span class="katex"><span class="katex-mathml"><math><semantics><mrow><msub><mi>T</mi><mi>c</mi></msub></mrow><annotation encoding="application/x-tex">T_c</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.83333em;vertical-align:-0.15em;"></span><span class="mord"><span class="mord mathdefault" style="margin-right:0.13889em;">T</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.151392em;"><span style="top:-2.5500000000000003em;margin-left:-0.13889em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathdefault mtight">c</span></span></span></span><span class="vlist-s">​</span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span></span></span></span> 约等于 <span class="katex"><span class="katex-mathml"><math><semantics><mrow><mn>977.5</mn><mi>n</mi><mi>s</mi></mrow><annotation encoding="application/x-tex">977.5ns</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.64444em;vertical-align:0em;"></span><span class="mord">9</span><span class="mord">7</span><span class="mord">7</span><span class="mord">.</span><span class="mord">5</span><span class="mord mathdefault">n</span><span class="mord mathdefault">s</span></span></span></span></li>
<li>时间周期 <span class="katex"><span class="katex-mathml"><math><semantics><mrow><mn>1</mn><mi>m</mi><mi>s</mi></mrow><annotation encoding="application/x-tex">1ms</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.64444em;vertical-align:0em;"></span><span class="mord">1</span><span class="mord mathdefault">m</span><span class="mord mathdefault">s</span></span></span></span></li>
<li>1个C/A码波长对应的长度<span class="katex"><span class="katex-mathml"><math><semantics><mrow><mn>299</mn><mi>k</mi><mi>m</mi></mrow><annotation encoding="application/x-tex">299km</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.69444em;vertical-align:0em;"></span><span class="mord">2</span><span class="mord">9</span><span class="mord">9</span><span class="mord mathdefault" style="margin-right:0.03148em;">k</span><span class="mord mathdefault">m</span></span></span></span></li>
<li>不同的卫星具有不同的C/A码</li>
<li>调制在L1载波</li>
<li>测距误差2.99~29.9m，精度较低</li>
</ul>
<h2 id="四-p码">四、P码</h2>
<h4 id="1-产生方法">1、产生方法</h4>
<p>P码由两组12级反馈移位寄存器产生</p>
<figure data-type="image" tabindex="1"><img src="http://cos.pansis.site/202310101523105.png/abc123" alt="image-20231010152317925" loading="lazy"></figure>
<h4 id="2-特性">2、特性</h4>
<p>时钟脉冲速率：10.23Hz</p>
<ul>
<li>码长： <span class="katex"><span class="katex-mathml"><math><semantics><mrow><mn>6.187</mn><mo>∗</mo><mn>1012</mn><mi>b</mi><mi>i</mi><mi>t</mi></mrow><annotation encoding="application/x-tex">6.187*1012bit</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.64444em;vertical-align:0em;"></span><span class="mord">6</span><span class="mord">.</span><span class="mord">1</span><span class="mord">8</span><span class="mord">7</span><span class="mspace" style="margin-right:0.2222222222222222em;"></span><span class="mbin">∗</span><span class="mspace" style="margin-right:0.2222222222222222em;"></span></span><span class="base"><span class="strut" style="height:0.69444em;vertical-align:0em;"></span><span class="mord">1</span><span class="mord">0</span><span class="mord">1</span><span class="mord">2</span><span class="mord mathdefault">b</span><span class="mord mathdefault">i</span><span class="mord mathdefault">t</span></span></span></span></li>
<li>码元宽度 <span class="katex"><span class="katex-mathml"><math><semantics><mrow><msub><mi>T</mi><mi>c</mi></msub></mrow><annotation encoding="application/x-tex">T_c</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.83333em;vertical-align:-0.15em;"></span><span class="mord"><span class="mord mathdefault" style="margin-right:0.13889em;">T</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.151392em;"><span style="top:-2.5500000000000003em;margin-left:-0.13889em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathdefault mtight">c</span></span></span></span><span class="vlist-s">​</span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span></span></span></span> 是C/A码的十分之一，约等于 <span class="katex"><span class="katex-mathml"><math><semantics><mrow><mn>0.1</mn><mi>n</mi><mi>s</mi></mrow><annotation encoding="application/x-tex">0.1ns</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.64444em;vertical-align:0em;"></span><span class="mord">0</span><span class="mord">.</span><span class="mord">1</span><span class="mord mathdefault">n</span><span class="mord mathdefault">s</span></span></span></span></li>
<li>时间周期 <span class="katex"><span class="katex-mathml"><math><semantics><mrow><mn>1</mn><mi>m</mi><mi>s</mi></mrow><annotation encoding="application/x-tex">1ms</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.64444em;vertical-align:0em;"></span><span class="mord">1</span><span class="mord mathdefault">m</span><span class="mord mathdefault">s</span></span></span></span></li>
<li>不同的卫星具有不同的P码</li>
<li>调制在L1 L2 载波</li>
<li>测距误差0.29~2.99m，精度较高</li>
</ul>
<br />
                                            
                                </p>
                            </div>
                            <div class="post_footer">
                                
                                    <div class="meta">
                                        <div class="info"><span class="field tags"><i class="iconfont icon-tag-sm"></i>
                                                
                                                    <a href="https://github.pansis.site/tag/zhdhyl/" class="article-info">
                                                        组合导航原理
                                                    </a>
                                                    
                                            </span>
                                        </div>
                                    </div>
                                    
                                        
                            </div>
                        </div>
                        
                            
                                <link rel="stylesheet" href="https://unpkg.com/gitalk/dist/gitalk.css">
<script src="https://unpkg.com/gitalk/dist/gitalk.min.js"></script>
<div id="gitalk-container" style="padding-bottom: 20px;"></div>
<script>
    var pageId = (location.pathname).substring(1, 49) // Ensure uniqueness and length less than 50
    pageId = pageId.endsWith('/') ? pageId.slice(0, -1) : pageId // 以斜杠结尾则去除
    var gitalk = new Gitalk({
        clientID: '9d5eba33618472c44a07',
        clientSecret: '065a85ed04333ceebfc4f01d7ca1674175730339',
        repo: 'fzxl2003.github.io',
        owner: 'fzxl2003',
        admin: ['fzxl2003'],
        id: pageId,
        distractionFreeMode: false  // Facebook-like distraction free mode
    })
    gitalk.render('gitalk-container')
</script>
                                    
                                        
                                                    
                    </div>
                </div>
            </div>
    </div>
    <div class="footer">
    
    <div class="powered_by">
        <a href="https://codeberg.org/kytrun/gridea-theme-one" target="_blank">Theme One,</a>
        <a href="https://open.gridea.dev/" target="_blank">Powered by Gridea&#65281;</a>
    </div>
    
    
        <div class="footer_slogan">
            Powered by <a href="https://github.com/getgridea/gridea" target="_blank">Gridea</a>
        </div>
    
    <div id="back_to_top" class="back_to_top">
        <span>△</span>
    </div>
    
</div>

<script src="https://github.pansis.site/media/scripts/util.js"></script>
        <link rel="stylesheet" href="//unpkg.com/@highlightjs/cdn-assets@11.5.1/styles/default.min.css">
        <script src="//unpkg.com/@highlightjs/cdn-assets@11.5.1/highlight.min.js"></script>
        <script>hljs.highlightAll();</script>
</body>

</html>